<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    let arr= [1,2,5,1,5,1,5,4,6,8,9]
    let newArr = [...new Set(arr)]
    console.log(newArr.sort((a,b) => a-b))

    // arr.__proto__  等于Array.prototype
    // arr.__proto__ = null;
    Array.prototype = null // 无效? 为什么
    Array.prototype.defineProperty()
    console.log(Array.prototype)
    newArr.splice(1,2,3,4)
    console.log(newArr)

</script>
</body>
</html>